If you open a post and click on the icon between the save and the reply icon, it opens that particular post in the webbrowser. Might save some steps.
I think it open on the instance that it was posted and if it's not your home instance, you can't do much. A maybe more feasible way is saving the post, then going to your instance on your browser or another app that supports blocking and do it there.
Not from wefwef from what I can tell
Various apps (memmy) and Lemmy UI do have the feature to block communities
I blocked 196 and memes on my lemmy instance’s web UI, but I still see them in All on Wefwef. Not sure if I’m meant to or not, but it doesn’t seem like I should, or what’s the point of blocking?